Module 8 Population Genetics

4.8.2 page 3

Module 8: Lesson 2 Assignment

Retrieve your copy of Module 8: Lesson 2 Assignment that you saved to your computer earlier in this lesson. Complete the assignment. Save your completed assignment in your course folder. You will receive instructions later in this lesson on when to submit your assignment to your teacher.

Discuss

With the guidance of your instructor, and working with fellow students, prepare the following discussion material for debate.) Half of the class should take the part of ranchers and the public in the surrounding area; the other half should take the part of wildlife managers. Prepare your position and discuss your findings with fellow students on the discussion board.

Debate the advantages and disadvantages of introducing the grey wolf back into Montana’s Glacier National Park. (Refer to Fig 19.10 on page 691 for more background information.)

Self-Check

1. Which gene pool would most likely demonstrate micro-evolution?
   
   
   1. A gene pool in Hardy Weinberg equilibrium
   2. A gene pool bearing a new mutation
   3. A large gene pool
2. Which correctly matches a term to its description?
   
   
   1. gene flow – a chance change in allele frequencies when small populations become isolated
   2. natural selection – a particular phenotype of mate is more often chosen
   3. change in mutation rate – several new mutations arise in a short period of time
   4. genetic drift – unrepresentative populations are separated from a larger population

Lesson Summary

The five causes of changes in frequency of alleles in the gene pool (micro-evolution) are:

1. Genetic drift – changes due to small populations. Typically decreases diversity. Examples are Founder and Bottleneck effects
2. Natural selection – Organisms with certain phenotypes/genotypes have selective advantage over others. This typically decreases diversity, especially in very competitive environments. Heterozygotes typically have the same advantage as the homozygous dominant genotype unless there is a heterozygote advantage
3. Change in mutation rates – a greater rate of mutation from one allele to the other – increases the frequency of one allele over the other. Typically decreases diversity. Mutations resulting in new alleles increase diversity
4. Non-random mating – choosing one allele over another in preferred mates is known as sexual selection and increases the frequency of one allele over the other, typically decreasing diversity
5. Gene flow - immigration and emigration increases diversity within populations, but decreases diversity between populations

Submit your completed Module 8: Lesson 2 Assignment to your teacher for assessment.